1. Field of the Invention
The present invention relates generally to vehicle launch systems, and more specifically to a vehicle launch system having an acoustic insulator for absorbing the acoustic energy generated during the initial stages of a space vehicle launch.
2. Description of the Prior Art
Traditionally, launchable spacecraft vehicles are enclosed in a protective shroud and mounted onto a high power launch vehicle which is used to propel the spacecraft vehicle into space. During the first three minutes of a launch, a significant amount of acoustic noise (or vibration) is generated at the launch vehicle, traveling up the sides of the spacecraft vehicle where it is conducted off the interior surface of the protective shroud. This conduction of the acoustic energy within the confined area between the spacecraft and the shroud causes the spacecraft components and electronics to be subjected to a high concentration of acoustic vibration. The acoustic vibration reaches levels that may cause structural damage to the spacecraft vehicle components and electronics.
Present launch systems use a variety of techniques to reduce the impact of acoustic vibration on the launchable spacecraft. One such technique requires spacecraft vehicle components that are structurally robust and have unique energy absorbing characteristics sufficient to survive extreme acoustic vibration. A second technique provides the use of a barrier between the source of the acoustic vibration and the spacecraft vehicle. The barrier is created by filling the area between the shroud and the spacecraft vehicle with a gaseous material that insulates the spacecraft from the extreme acoustic environment. However, each of the described conventional approaches has inherent drawbacks.
Regarding the first technique, building structurally robust components that are energy absorbent may require heavier components, special materials and additional design steps. As the overall weight of the spacecraft is increased, the amount of fuel required launching the spacecraft increases. Special energy absorbing materials and additional design steps further increase the spacecraft vehicle fabrication costs.
Regarding the second technique, creating a barrier from gaseous materials, typically helium, has been found to enable low voltage arcing within the electronic circuitry of the spacecraft vehicle. The low voltage arcing occurs when the unconfined gaseous material seeps into the electronic circuitry of the spacecraft.
Based on the techniques known in the art for reducing the acoustic vibration effect on launchable spacecraft vehicles, a vehicle launch system having an acoustic insulator which, maintains vehicle weight limitations, decreases overall launch costs and eliminates low voltage arcing effects is highly desirable.